Accidental cannabis ingestion in young children

Unintentional marijuana ingestion

Young children, especially those younger than 6 years old, are at risk of unintentional or accidental marijuana exposure.⁸ Unintentional marijuana ingestion in children younger than 5 years old accounted for 41.6% of all poison control encounters in the United States in 2020.⁹ Between 2017 and 2021 in the United States, 36.2% of cases of marijuana ingestion reported in this age group were treated and discharged from the emergency department (ED), 14.6% were admitted to the general care floor, and 8.1% were admitted to the intensive care unit.⁹ These represented increases in hospital and health care resources across multiple medical environments and raised awareness of pediatric marijuana ingestion as a public health concern.

Private residences are the most common location for accidental ingestions.^10,11 Children indiscriminately explore familiar environments and often discover marijuana kept in the home. Unfortunately, many labels and packaging used for cannabis products are made to resemble popular candy or snacks, placing children at risk for consumption.⁸ Homemade products, easy-to-open packaging, and enticing flavours further increase the risk of unintentional ingestion in children.⁸ While regulations are in place to protect children from ingesting dangerous materials, cannabis products were not included in the original literature of the law. In 1970 in the United States, the Poison Prevention Packaging Act was passed with the intention of preventing children from accidental exposure to harmful chemicals, such as bleach, cleaning solutions, and prescription medications.¹² However, regulation for packaging of cannabis products does not fall under the act and remains unregulated. Since that time, Canada published regulations for the commercial production and packaging of cannabis-containing products with the intention of reducing the risk of accidental ingestion; this includes warning labels, plain-text requirements, and child-resistant packaging. This is an important step toward reducing the incidence of unintentional ingestions.¹³

Symptoms of marijuana toxicity

Marijuana toxicity symptoms range from mild to severe and can have a range of presentations. In a case series from British Columbia, marijuana toxicity caused altered mental status in an 11-month-old with acute-onset hypotonia and decreased responsiveness; excessive sleepiness and poor balance after waking up from a nap in a 3-year-old; and nausea, pallor, and loss of consciousness in a 4-year-old.¹⁴ All these cases were marked by a sudden change in the patient’s level of consciousness and mental status.¹⁴

Mild symptoms of marijuana toxicity in children are somnolence, nausea, vomiting, mydriasis, and conjunctival erythema.⁹ Patients with abnormal heart rates usually have tachycardia but can have bradycardia. Hypotension is the main blood pressure abnormality.^7,9 Symptoms of severe toxicity include respiratory depression, respiratory failure, altered mental status, ataxia, hypotonia, seizure, and unresponsiveness.^9,15

Risk of overdose

Children younger than 6 years old are at higher risk of severe toxicity and overdose from accidental marijuana ingestion because of factors related to the developmental stage and the types of marijuana in circulation. In the 2024 Canadian Cannabis Survey, the most commonly consumed edibles were foods that are highly appetizing for children, such as gummies (91%), chocolate (37%), cookies (18%), and brownies (15%).⁶ Many of these edible products contain multiple doses, with some single edible items containing up to 500 mg of tetrahydrocannabinol (THC). Although no standard dosing guidelines have been established for recreational marijuana use, some studies proposed 5 mg as a standard unit of measurement for THC.¹⁶ Doses of 1 to 5 mg are considered microdoses and 100 mg or greater is considered a very high dose.¹⁷ Children are at risk of consuming an entire product indiscriminately, which may contain high levels of THC, especially when marketed as an enticing candy or encountered as a palatable homemade item.

In a retrospective review, the American Academy of Pediatrics reported data that outlined the weight-based impact of marijuana ingestion in children.¹⁵ In cases where the ingestion dose was reported, the weight-based dose was a substantial predictor of severe toxicity and duration of symptoms in accidental ingestions. Symptoms typically presented 2 to 4 hours after ingestion, and patients with severe toxicity experienced symptoms for more than 6 hours. Almost half (46%) of cases were considered severe; intravenous fluids or vasopressors were used to manage cardiovascular depression, requirement of supplemental oxygen, respiratory failure, seizures, or unresponsiveness.¹⁵ The authors concluded a 3-year-old of 25th percentile weight (13 kg) with access to 2 or more 10-mg serving sizes of THC (around 1.7 mg/kg) would place the child at risk of severe toxicity. This study recommended any child with a reported history of high-dose ingestion should be monitored for at least 4 to 6 hours until return to baseline, and in a facility where they could be admitted for treatment.^15,18

Workup and management

Owing to regulatory changes in Canada and the United States in the past decade, unintentional marijuana ingestion should be highly considered in the differential diagnosis of patients younger than 6 years old presenting with acute onset of somnolence, altered mental status, lethargy, or similar symptoms. Patients presenting with mild symptoms, such as conjunctival erythema, somnolence, and drowsiness, are at risk to worsen clinically based on the dose and timing of ingestion. The ED is the best clinical setting for monitoring and observing patients who may have ingested cannabis. A urine drug test, blood glucose test, electrocardiogram, blood gas analysis, and head imaging scan should also be considered. In cases of severe toxicity requiring more invasive interventions, transfer to a facility with pediatric wards and an intensive care unit is recommended.¹⁹ If a patient has not returned to their baseline after 6 hours, it is generally recommended the patient be admitted for further monitoring.